help needed - newbe - Debug on WinXP

Hi,
Can anybody explain me step by step how I can debug winvnc.
I've downloaded the source code in c++ but if I say: "compile with
batch" (sorry I have the german version so I don't know how the commands
are correct),
in the dialog I marked all and said compile all new.
The result is: 17 Errors and 12 warnings.
How can this be? I haven't done any changes.
To understand the code is not easy for me so I thought it would be
useful if I can debug the code step bye step to see how vnc works.
Thank you 4 your help!!!
Pascal